To its credit, GM's steep decline, like Ford's, was probably due in part to its reluctance to engage in the heavy discounting some rivals favor. But unlike Ford, there are mounting questions as to whether GM's European operation is on the road to recovery.

Ford's decisive action versus GM's incremental changesIt's impossible to ignore the contrast. In the face of mounting losses in the region last year, Ford's top brass confronted the issue head-on, announcing a comprehensive plan to restore the Blue Oval's European division to profitability.

Ford's plan includes factory closures, a product-line expansion, and a shift in marketing strategy. Analysts and industry experts give it a good chance of success. And importantly, Ford CEO Alan Mulally and his team have made it clear: If more cuts are needed, they'll make more cuts.

On the other hand, there's General Motors.

GM has been losing big money in Europe for years -- more than $15 billion since 1999. And there are more losses on the way: GM's Europe losses are expected to total $1.5 billion or more when the automaker reports full-year 2012 earnings next month.

Fed up with the trend, CEO Dan Akerson moved Europe to the top of his priority list late in 2011. He dispatched key members of his brain trust to Europe with a mission: Fix Opel once and for all.

From that dramatic start, many expected decisive action. But so far, it hasn't come.

A lot of change, but how much progress?GM has certainly been busy. Management changes at problematic German subsidiary Opel, a parts-sharing alliance with Peugeot that may (or may not) lead to a larger tie-up, plans for new products, and a plant closing scheduled for the end of 2016 have all been announced, and most represent real progress -- to some extent.

GM Vice Chairman Steve Girsky, who is spearheading the Opel turnaround, said last fall that the changes made so far should be enough for Opel to break even by "mid-decade."

But analysts remain skeptical. Morgan Stanley's Adam Jonas, perhaps the highest-profile auto analyst on Wall Street, thinks that one of Girsky's key assumptions -- that Opel won't lose market share from here -- is "way too bullish." He may have a point: Competition from the likes of VW and Ford -- the market leaders in Europe -- looks likely to intensify over the next few years. Winning back market share without resorting to steep profit-eroding discounts could prove to be a challenge.

Jonas made headlines last year, when he suggested that GM would be best off selling Opel -- even if it had to pay to get rid of the long-troubled German automaker. Reports earlier in January suggested that GM was preparing to do as he suggested, as a French newspaper reported that Opel was set to be given to Peugeot, perhaps with a several-billion-euro incentive from GM to sweeten the deal.

Staying the course and expecting improvementAkerson shot down those rumors on Monday, saying that Opel is "not for sale." Meanwhile, the company expects Europe's auto market to weaken further in 2013 but also predicts that it will record a modest gain in market share in the region next year.

Is that too optimistic? We'll find out. But while the measures taken to address GM's chronic losses in Europe may ultimately bear fruit, many analysts -- and shareholders -- are still thinking that more big changes need to be made. Watch this space.

It's true that decades of mismanagement of General Motors led to a painful bankruptcy in 2009, but it emerged a leaner, stronger company. GM's turnaround, however, is still a work in progress. Investors around the world are wondering if GM has what it takes to reclaim its former glory. I've put together a brand-new premium research report telling you what you need to know about GM and its turnaround. If you own or are thinking about owning GM, then you don't want to miss this report. Click here now to get started.